github - How to move a branch backwards in git?

Question

The title is not very clear. What I actually need to do often is the following:

Let's say I have a development going on with several commits c1,c2,... and 3 branches A,B,C

c1--c2--c3--(B)--c4--(A,C)

Branch A and C are at the same commit.

Now I want branch A to go back where B is, so that it looks like this:

c1--c2--c3--(A,B)--c4--(C)

Important is that this has to happen locally and on GitHub.

Answer 1

Use the reset subcommand:

git checkout A
git reset --hard B
git push --force github

As a sidenote, you should be careful when using git reset while a branch has been pushed elsewhere already. This may cause trouble to those who have already checked out your changes.